Retrievable bridging plug



Sept. 27, 1955 Filed Sept. SO, 1952 P. R. SCHLEGEL RETRIEVABLE BRIDGING PLUG 2 Sheets-Sheet l #www Sept 27, 1955 P. R. scHLEGEL RETRIEVABLE BRIDGING PLUG 2 Sheets-*Shee'l 2 Filed Sept. 30, 1952 nited States Patent RETRIEVABLE BRIDGING PLUG Paul R. Schlegel, Oklahoma City, Okla., assigner, by

mesne assignments, to Lane-Wells Company, Los Angeles, Calif., a corporation of California Application September 30, 1952, Serial No. 312,199

2 Claims. (Cl. 166-135) This invention relates generally to well packing devices, and more especially to bridging plugs and tools to plug or close off the casing at some point above the bottom of the well.

Packing devices or bridging plugs are commonly employed in well casings for sealing oli, the lower portion of the well or to separate upper and lower sections thereof for various purposes. In many instances, after a bridging plug has been set in a well for a period of time, it is desirable or becomes necessary to remove the plug, and this is usually done either by `attempting to release the plug from the casing and to retrieve as much as possible thereof intact, or it may be necessary to destroy the plug by drilling methods which are well known. In the latter case it is essential that the plug be of a material which is readily drillable. However, such plugs are less desirable for many uses because of the necessity for making them of lighter and less suitable materials, which may impair their durability and usefulness while set or make it diiiicult for them to be retrieved by the usual retrieving tools.

The present invention is directed to a bridging plug, the packing portion of which is largely conventional in gene eral design and construction so as to be readily s'et in position, but which is adapted, after being set, to be manipulated in a novel manner to permit ready and complete release of the slips and packing element to permit the whole bridging plug assembly to be easily and quickly removed from the well casing.

It is therefore a general object of the invention to provide a bridging plug device that is of generally conventional form, but having a novel slip mounting mechanism which permits quick and complete release of the slips from the well casing and removal of the plug therefrom.

Another object of the invention is to provide a bridging plug of novel construction, which is readily retrievable by the use of substantially conventional retrieving tools.

An additional object of the invention is to provide a retrievable bridging plug which is easily constructed, having few parts, thereby providing a well tool which is particularly economical to manufacture.

The objects of this invention are attained, in brief, by providing a bridging plug having slips and retractable slip wedging members extending through slots in the mandrel and initially supported in extended position by a supporting member contained within the mandrel and which can be removed readily, thereby permitting the slips to retract from engagement with the surrounding borehole wall and, together with the slip wedges,.to fall inwardly into the interior of the bridging plug and to be retrieved therewith.

Other objects and advantages will appear and be brought out more fully in the following specification, reference being had to the accompanying drawings forming a part thereof and in which like reference characters refer to like parts. In the drawings:

Figure l is a longitudinal elevational view of the gen- FAice eral assembly of the bridging plug as it appears when suspended within a well casing just prior to setting;

Figure 2 is a longitudinal sectional view of the bridging plug of Figure l, showing its assembled -appearance just prior to setting in a well casing;

Figure 3 is a view similar to Figure 2, showing the apparatus just after completion of the setting stage;

Figure 4 is a longitudinal sectional view of the apparatus `during the initial retrieving stage;

Figure 5 is a view similar to Figure 4, showing the apparatus during the iinal retrieving stage; and

Figure 6 is an enlarged sectional view taken along line 6 6 of Figure 5.

Referring more particularly to the drawings, the packer portion or body of the apparatus is shown within a well casing C and comprises a centrally located, elongated, tubular body or mandrel 10 of substantially uniform external diameter throughout its length and closed and terminated at its lower end by a nosepiece or shoe portion 11 of slightly increased diameter, an upwardly facing annular shoulder 12 being thus formed at the junction of the mandrel body and said shoe portion. The mandrel 10 is hollow and has a substantially uniform bore 13 except for an upper end portion of reduced internal diameter 14 threadedly connected thereto at 14a and forming an inner, downwardly facing, annular shoulder 1S, and an upper, upwardly facing, beveled portion 16 to facilitate the entrance of a retrieving tool into bore 13. A shear pin 17, which extends diametrically through the upper end portion 14, serves to connect the mandrel 10 with a setting tool tension member 17a. Substantially at its middle the mandrel 10 is provided with a plurality of axially elongated, window-like `apertures or slots 18 extending laterally through the walls thereof, in which the slips 32 and slip inclines or wedges 27 may be laterally slidably positioned. A slip retaining member 20, which is shown as being cylindrical and tubular, but which may be solid if desired and of any other suitable shape, is longitudinally slidably contained within bore 13 of the mandrel 10 and is initially secured in position against longitudinal sliding motion therein behind the slots 18 by a plurality of shear pins 21 which pass radially through the top portion of the slip retaining member 20 and the mandrel 10 at a suitable location above slots 18. A transverse bar 22 extends through diametrically opposite holes in the walls and across the bore of slip retaining member 20 at a convenient point, preferably near the top end thereof, for engagement with the hook element of a retrieving tool or other suitable device, as may be desired. A lower expander sleeve 23 surrounds mandrel 10 and rests on the annular shoulder 12 of the shoe or nosepiece 11, and a resilient, longitudinally compressible, radially expansible packing element 24 is positioned on the mandrel above the expander sleeve 23. An upper movable packing expander sleeve 2S is slidable on the mandrel above packing element 24 and normally extends.

of expander sleeve 25. The base of each slip wedge is formed with a downwardly depending retaining lug 310 which extends into the annular space between the upper end of the expander sleeve 25 and the inner surface of the retaining member 20. Each slip wedge is also formed with an upwardly and inwardly inclined surface 31 for sliding engagement with a similar surface on the slip` supported thereon. A wedge-shaped slip 32 is carried pn each one of the slip wedges 27 and is formed with an inclined surface 33 for longitudinal sliding engagement wlth .the before-mentioned matching surface 31 of the associated slip wedge 27. Each slip is initiallysecured to lts slip wedge, against relative sliding motion between surfaces 31, 33, by a shear screw 34. Each slip 32 is formed with downwardly directed wickers 35 and upwardly directed wickers 36, and by this arrangement of the wickers the packer when set will be held against movement either upwardly or downwardly within the well casing. A spacer sleeve 37 is located on the mandrel above the slips 32, with its lower end initially 1n abutment with the upper, base ends of the slips 32 and with its upper end in abutment with the lower end of a tubular ram adapter member 38, the lower end of which carries a lock ring adapter 39 connected thereto by threads 40. Lock ring adapter 39 has an internal annular recess 41 inwhich is disposed a split latching ring 42 having upwardly directed wickers for ratcheting engagement with a downwardly directed wickered portion 43 of mandrel 10. Expander sleeves 23 and 25 are each formed with a beveled end portion 44 and an enlarged end bore 45, and the adjacent ends of packing sleeve 24 are undercut at 46 and provided with slits 47, forming thereby outer annular end portions 43 tapered or beveled at 49 and inner pressure lips 50. The inner pressure lips 50 are adapted to extend into bores 45 when the beveled ends 51 of the expander sleeves move into slits 47 of the packing body upon setting of the packer.

In the operation of the invention, the bridging plug is attached to a suitable settng tool and then lowered into the well casing on either a wire line, cable, or tubing to the point at which it is to be set. Suitable wire line setting tools are disclosed in Hart No. 2,308,004, Spangler No. 2,326,404, Batchelder No. 2,382,770, and Forsyth et al. No. 2,566,323. In any case the setting tool is attached to the bridging plug with the lower end of the setting tool cylinder or body portion coupled to the upper end of the ram adapter member 38, and with the pull rod or piston 17a of the setting tool connected by means of shear pin 17 to the upper end of the mandrel 10. When the plug has been positioned at the desired level, the setting tool is actuated to apply tension to the pull rod 17 and to apply an equal and opposite downward force from the setting tool cylinder to the top of the ram adapter 38. These forces will be effective to move the mandrel upward relative to the ram adapter 38 and the spacer sleeve 37, thereby causing force to be applied downward through the spacer sleeve 37, slips 32, slip wedges 27, and upper expander sleeve 25 to the top end of the packing element 24, and an equal and opposite force to be applied upwardly from the shoulder or abutment 12 through the lower expander sleeve 23 to the lower end of the packing element 24, thereby expanding the slips and packing element 24 into rm engagement with the surrounding wall-of casing C. During this movement, mandrel 10 will be moved upwardly relative to locking ring 42, which ring will be brought into ratcheting engagement with the wickers 43 of the mandrel to lock the bridging plug in set condition. After the plug has been thus set, continued operation of the setting tool resulting in continued increase in tension in the pull rod 17a will eventually cause the pin 17 to shear, thereby disconnecting the pull rod 17a from the mandrel and thereby freeing the whole setting tool from the bridging plug, after which the setting tool can be withdrawn from the casing.

When it is desired to remove the plug from the borehole or casing in which it has been set, a retrieving tool, carrying on its lower end a suitable hooking device or grapple adapted to make connection with the transverse bar 22, is lowered down the borehole and through the top of the ram adapter 38 into the bore 13 of the upper portion of the mandrel and suitably hooked or latched to bar 22 of the slip-retaining member 20. Upon upward movement of the retrieving tool, shear pins 21 will rst shear, permitting the retaining member 20'to be raised within the bore 13 of the mandrel 10 from the position shown in Figure 3 to that shown in Figure 4, such that the lower end of the retaining member 20 is located above the upper ends of the slip wedges 27 and slips 32, whereupon the slip wedges are no longer supported from within by the retaining member 20, and are freed to slide inwardly through the window slots 1S and drop into the lower end of the mandrel. The packing expander 25, thus relieved of the restraining action of the slips 32 and Wedges 27, moves upwardly on the mandrel 10, permitting the packing element 24, by reason of its resiliency, to expand longitudinally and contract radially, thereby freeing itself from the wall of the surrounding casing. Upon continued upward movement of retaining member 20 within mandrel 10, the upper end of member 20 will engage the annular shoulder 15, and the ram adapter 3S and spacer sleeve 37, now unsupported, will slide downwardly over the mandrel 10 until the lower end of spacer sleeve 37 comes to rest on the upper end 29 of expander sleeve 25, and the plug may then be lifted out of the casing. The plug thus removed from the well may subsequently be reassembled for reuse.

As an alternate feature, the slip retaining member 20 may be made omitting the transverse bar 22 and can be raised by an expanding type of tube grip or retrieving tool employing slips or the like well known type of apparatus adapted to be inserted into gripping engagement with the interior surface of the bore of the retaining member 20.

It is to be understood that the foregoing is illustrative only, and that the invention is not limited thereby, but may include various modifications and changes made by those skilled in the art without departing from the scope of the invention as dened in the appended claims.

What is claimed is:

l. In a bridging plug, the combination of: a mandrel formed with an external abutment and having a plurality of circumferentially spaced-apart, axially elongated slots extending laterally through the wall thereof; a packing expander sleeve slidable on and surrounding said mandrel; a resilient packing sleeve surrounding said mandrel intermediate said abutment and the inner end of said expander sleeve; a slip wedge retaining member slidable longitudinally within said mandrel and covering said slots; means initially securing said retaining member against longitudinal sliding movement in said mandrel and in position opposite said slots; an internal abutment on said mandrel; slip wedges extending laterally slidably through said slots and disposed with the longitudinally extending edges thereof in abutment with the outer surface of said retaining member and with the bases thereof in abutment with the outer end of said packing expander sleeve; slips longitudinally slidably retained on said slip wedges; sleeve means slidable longitudinally on said mandrel and engageable with a setting tool for application of setting force thereto for moving said slips up said wedges and said packing expander sleeve axially on said mandrel toward said external abutment for expanding said packing sleeve therebetween and setting said slips; means for locking said sleeve meanson said mandrel against retrograde movement thereon after such movement and retrieving tool engaging means for shifting said retaining member longitudinally upwardly away from a position opposite said'slip wedges and into engagement with said internal abutment, whereby said slip wedges are permitted to move radially inward to release said slips and permit said packing sleeve to contract and said mandrel to be shifted.

2. In a bridging plug, the combination of: a hollow mandrel formed with an external abutment and having a plurality of circumferentially spaced-apart, axially elongated slots extending laterally through the wall thereof; a packing expander sleeve slidable on and surrounding said mandrel; a resilient packing sleeve surrounding said mandrel intermediate said abutment and the inner end of said expander sleeve; a slip wedge retaining member slidable longitudinally within said mandrel and covering said slots; means initially securing said retaining member against longitudinal sliding movement in said mandrel and in position opposite said slots; an internal abutment on said mandrel; slip wedges extending laterally slidably through said slots and disposed with the longitudinally extending edges thereof in abutment with the outer surface of said retaining member and with the bases thereof in abutment with the outer end of said packing expander sleeve', slips longitudinally slidably retained on said slip wedges; sleeve means slidable longitudinally on said mandrel and rengageable with a setting Atool for application of setting force thereto for moving said slips up said wedges and said packing expander sleeve axially on said mandrel toward said external abutment for expanding said packing sleeve therebetween and setting said slips; means for locking said sleeve means on said mandrel against retrograde movement thereon after such movement and retrieving tool engaging means for shifting said retaining member longitudinally upwardly away from a position opposite said slip wedges and into engagement with said internal abutment, whereby said slip wedges are permitted to move radially inward to release said slips and permit said packing sleeve to contract and said mandrel to be shifted.

References Cited in the le of this patent UNITED STATES PATENTS 2,308,004 Hart Ian. 12, 1943 2,323,085 Davis June 29, 1943 2,326,404 Spangler Aug. 10, 1943 2,382,770 Batchelder Aug. 14, 1945 2,566,323 Forsyth et al. Sept. 4, 1951 

